Larry Masinter writes:
> The point that is trying to be made is that an entity tag can only
> be used relative to the same requested resource. Personally, I wish
> Etags were stronger than this, but that is their definition.
At the time we discussed this, it was believed that we could at some
later date add other kinds of ETags with a broader scope (server
unique or even globally unique).
I think the possibility is still open to do this, in a separate
specification. Old clients/proxies would just see the new ETag as
having a narrower scope of uniqueness.
Actually, there has a proposal on the table, since January:
http://www.ics.uci.edu/pub/ietf/http/draft-mogul-http-delta-00.txt
which includes a careful definition of "uniqueness scope"
and "a means to extend the uniqueness scope to include
multiple resources," although that is not the primary purpose
of this draft. Constructive comments are encouraged.
-Jeff